Question

Lasers 1 and 2 emit light of the same color, and the electric field in the beam from laser 1 is twice as strong as the field in laser 2’s beam. How do their (a) magnetic fields, (b) intensities, and (c) wavelengths compare?

Answer 1

a)
Magnetic field, B = E/c, where c is the velocity of the light.
They are directly proportional, So the magnetic field in the beam from laser 1 is twice as strong as the field in laser 2’s beam.

b)
Intensity is given by I = 1/2 c _{$\epsilon_o$} E².
Intensity in the beam from laser 1 is 4 times as strong as the field in laser 2’s beam.

c)
Velocity, c = f $\lambda$
Since they have same frequency (same color), they will have same wavelength.